Evaluation of Biochar Liquid Extract for Control of Boxwood Blight

Boxwood blight, caused by the fungal pathogen Calonectria pseudonaviculata, is an emerging disease that has devastated the boxwood industry and private/public gardens. Here, we evaluated the potential of biochar liquid extracts for controlling boxwood blight disease. Three biochar products from pine, eucalyptus, and citrus were tested at 0.5, 1.5 and 3% (w/v) concentrations on 2-year-old container-grown Buxus sempervirens ‘Justin Brouwers’ plants under controlled conditions. Although none of the three products at three concentrations evaluated were effective in protecting boxwood from the blight pathogen, this study provided insights into the use of biochar as a management strategy for foliar diseases.